Valve for fluid-operated motors



Oct. 25, 1938. c. J. cosi-:RLY

VALVE FOR FLUIDOPERATED MOTORS 4 Sheets-Sheet l Filed April 2l, 1937 4 Sheets-Sheet 2 w R UR m M @a mlvw r.m e mum N www, f EC .r Rm MA M C, R R o8/VM, .muMh/ f vC. J. COBERLY Filed April 2l, 1937 VALVE FOR FLUID-OPERATED MOTORS oct. 25, 193s;

Oct. 25, 1938. c. J. coBERLY 2,134,174

VALVEFOR FLUID'OPERATED MOTORS Filed April 21. 1937 4 sheets-sheet 5 4,3 CLARENCE J. CoERLy Oct. 25, '1938. J. coal-:RLY 2,134,174

VALVE FOR FLUID-OPERATED MOTORS Filed Apnl 21., 1957 4 sheets-sheet 4 l U U U f' n n n n n n f /54 J u U U U U U U` /Gg @3f /56 l f o (o) (n) (n) n 76? /56 //48 9 PL UNSER TRA VEL /NCHEQ VA VE VfL-TENTMS T/ME /N JECONDO I/vVE/v TOR CLARE/VCE u. COBERLV HARR/ /f/'Ecn Fear/SR d HAR/2m A T'T R/VEYJ.

Patented Oct. 25, 193s' PATENT OFFICE VALVE Fon FLUID-OPERATED morons Clarence J. Coberly, Los Angeles, Calif., assignor to Itoko Corporation, Reno, Nev., a corporation of Nevada Application April 21, 1937, Serial No. 138,176

9 Claims. (Cl. 121-151) This application is a continuation-impart of my copending Patent No. 2,081,223, issued May 25, 1937, for Fluid operated deep well pump, and a continuation-impart of my pending application Serial No. 720,057, filed April 11, 1934, for Liquid operated motor.

The present invention relates to a valve structure for a fluid-operated motor, and is of especial utility in fluid motors for use with fluid-operated pumps disposed at the bottoms of deep wells for the. purpose of pumping oil therefrom, and for this reason it is deemed advisable to disclose the invention in connection with such a pump. As is well known, the conditions encountered in drilling deep wells make it necessary to reduce the size of casngs or liners as the well is continued downwardly. As a result, at the bottom of a deep well the pipe which enters the oil formation may often be of Very small diameter, for instance, from tWo or three inches. 'Ihe space limitations thus produced'make the design of deep well pumps exceedingly diicult, especially with relation to that type of pump known as a fluid-operated pump, in which the pumping piston and a motor therefor are combined invone small structure which is disposed within the casing at substantially the bottom of the Well.

My invention 'contributes tothe making of a pump of this character which will operate satisfactorily for relatively long periodsof time and with high eiliciency as compared with pumps known in theart at the present time.

It is an object of the invention to provide a valve for a fluid-operated pump mechanism, which controls the delivery of fluid under pressure to the motor cylinder of the pump, the valve beinguid operated and positive in its action.

A further object of the invention is to provide a valve mechanism having asliding valve part which is moved between primary and secondary positions and controlled by fluid pressure, and which has means for holding the valve in such positions during periods when movement thereof is not intended. l

It is an object of the invention to provide means for controlling the flow and application of fluids under pressure in the mechanism in such a manner thatv sudden shock of uid pressure in the mechanism during operation thereof is avoided.

It is another object of the invention to provide astructure accomplishing the function set forth in the preceding paragraph which includes a sliding valve moving between primary and secondary positions to alternately open passages for supplying uid under pressure to opposite ends of a. power cylinder which in turn controls a pumping cylinder, the valve being controlled by a novel form of throttling means to-move slowly during the initial opening of the passages, at which time oil is first admitted to the pump cylinder, and to accelerate during the completion of its movement to fully open the passages.

In the operation of the device', as will be explained hereinafter, the uid pressures in the uid passages and chambers gradually build up and recede, and the moving parts have controlled acceleration and deceleration. In such a manner, the structure of the pumping device is to the greatest possible extent relieved of Vthe sudden application offorces and the shocks resulting 15 therefrom.

It is another object to provide a valve mechanism which controls the rate of valve movement in each direction independently. y

It is another object to provide a means to cause a valve to move rapidly for a given part of its travel, very slowly for a given part and then with increasing speed to the end of its travel, 'and independent means of obtaining similar action when the valve is moved in the opposite direction.

Another object is to provide a valve which will give a rapid cut off, a predetermined period between 'cut oil and beginning of admission, slow initial admission with increasing speed, ending with a rapid flnal movement.

Further objects and features of the invention vwill be made clear in the following part of the specification taken in vconnection with the accompanying, drawings. /v

In the drawings: l .f

Fig. 1 is a vertically sectioned view showing the upper end of a fluid-operated pump embodying the features of my invention.

Fig. 2 is a vertically sectioned view complementary to Fig. 1 showing the central section of the pump.

Fig. 3 is a vertically sectioned view complementary to Fig. 2 showing the lower end section of the pump.

Fig. 4 is a slightly enlarged cross section on a plane represented by the line l-4 of Fig. 1.

Fig. 5 is an enlarged cross-section on a plane represented by the line 5-5 of Fig. 1.

Fig. 6 is a cross-section on a plane represented by the line 6--6 of Fig. 1.

, Fig. '7 is an enlarged cross-section on a plane represented by the line 1-1 of Fig. 1.

Fig. 8 is an enlarged cross-section on a plane represented by the line 8-8 of Fig. 1.

Fig. 9 is a cross-section on a plane representedA by the line 3-3 of Fig. 1.

Fig'. 10 is an enlarged cross-section on a plane represented by the line .i3-I3 of Fig. l.

Fig. 11 is an enlarged cross-section on a plane represented by the line II-II of Fig. 1.

Fig. 12 is an enlarged cross-section on a plane represented by the line |2-I2 of Fig. 1.

Fig. 13 is a fragmentary section on a vertical plane taken as indicated by the line I3 of Fig. 1l.-

Fig. 14 is an enlarged vertically sectioned -view of the valve member forming a part of the invention, in connection with fragmentary portions of the valve body and valve liner of the structure are shown.

Fig. 15 is a view showing the surface of the valve member i4 projected onto a vertical plane for the purpose of showing grooves formed in the surface of the valve member.

Fig. 16 is a. vertically sectioned view corresponding to Fig. 1, but showing the valve member and the pilot member of the structure in their respective lowered positions.

Fig. 1'1 is a fragmentary sectional view showing the valve member as it approaches lowered position.

Fig. 18 is a fragmentary sectional view similar to Fig. 1'1, showing the valve member as it approaches raised position.

Fig. 19 is a space-time diagram of the valve movement and piston movement of the pump in which the ordinates 4represent time in seconds and the abscissa represents the valve travel in tenths of an inch and the plunger travel in inches, the diagram clearly illustrating the relative movement of the valve and piston and also the rate of movement throughout one complete cycle.

In the pump structure I3, Figs. 1, 2, and 3, embodying my present invention, I employ an upper tting'23 by 'which the pump structure is secured to the lower end of a fluid delivery pipe 2i by which operating iiuid under relatively high pressure is delivered to the motor section of the pump structure I3. 'I'he fitting 23 has athreaded'portion 22 for connection to the upper end of a valve body 23. The valve body 23 has an axial minor bore 24 formed in the upper part thereof, which minor bore 24 is separated by a circular channel 23 from a major bore 23 axially ormed in the lower portion of the valve body Substantially intermediately between the ends of the minor bore 24 is a circular channel 21 which communicates through ports 23 with the upper ends of primary iiuid passages 33 which extend within thewall of the valve body 23 to the lower end thereof. Spaced below the chan- "'nel 23 'in the major bore 2371s a plurality of secondary ports'3l communicating with the.. upper ends of secondary uid passages 32 which are formed coaxiallyfwithin the wall of the valve, body 23 and are placed between the passages 33, as shown in Fig. 6,- and which secondary passages 32 extend to the lower end of the valve body 23. As further shown in'Fig. 6, the ports 3| constitute circular depressions formed in the -inner face of the major bore 23, preferably by Y the use or circular milling cutters.

As shown in Fig. 5 and also in Fig. 1, a plurality of discharge ports 33 connect the channel 25 with a channel 34 formed in the outer face of the valve body 23. As shown in Figs. 1 and '1, an auxiliary discharge passage'33 .connects between the exterior of the valve body 23 and a small channel 33 formed within the major bore 23 below the ports 3|. As shown in Hgs. l, 8, and 13, a pasage 31 extends upwardly from the lower end of the valve body 23 in a position between two' of the passages 32, as shown by dotted lines in Figs. 6 and '1. The passage 31 accordingly is in the same vertical plane as the discharge passage 35 but stops below the passage 33. Connecting the upper end of the passage 31l with the exterior of the valve body 23 isa port 33.

To threads 43 formed at the lower end of the valve body 23, a power cylinder 4I is secured, this power cylinder having an axial chamber 42 formed in the upper end thereof for receiving a plug body 43 which is held in duid-tight engagement with the lower end of the valve body 23 and in fluid-tight engagement with`the upper end of a cylinder liner 44 when the power cylinder 4i is connected to the valve body 23 as shown. Mounted in the upper part of the plug 43 is a valve liner 45 having an upper end portion 43 extending upwardly within the major bore '2-3 of the'valve body 23 to a plane disposed a short distance below the ports 3l, there being any annular space 41 formed within the major bore 23 around the upper end portion. of the valve liner 45. Internally formed intermediate the ends of the upper portion 43 oi' the valve liner 43 is a channel 43 which communicates with the space 41 through a port 33, and near the lower end of the upper portion 43 is an annular channel 5I which communicates with the space 41 through a port 52. The channels 43 and Il, and the ports and 32 are shown in the crosssectional views, Figs. 9 and 10. A shoulder or collar 53 is formed on the valve liner 43 in a position to rest against the upper end of the plug body 43 and to reside within the lower extremity of the major bore 23. Below the horizontal plane of the collar 33, a channel 34' is formed, which, as shown in Figs. 1, 11, and 13,

"communicates through a port 33 in the wall ol the valve liner 45 and a passage 36 in the plug .bore in the lower. end of the e 31 so as to project into the .upper end of the passage 31, as shown in Fig. 13.

Slidable within the valve. body 23 is a piston valve 33 which is of tubular form and vhas a minor portion 33 which is separated by a radial shoulderl froma major portion'32. The minor portion 33 of the valve member 3 3 is of smaller diameter than the major portion 32 and has an external surface 63 which ilts the minor bore 24 of the valve body 23 in fluid-tight relation. 'I'he major portion 32 of the valve member 33 has an external surface 34 which is slidabievwithin and fits the major bore 23 of the valve'body 23 in fluid-tight relation. In the upper part lof ther minor portion 30 of the valve'member 5l are primary valve ports 33 which vconnect the bore 33 of the minor portion 33 with the-primary ports 23 at the upper ends of the' primary passages 33 when the valve member 3 3 is in lowered or primary position, as shown in Fig. 16. In the major the upper ends of the secondary passages 32,

when the valve member 58 is in raised or secondary position, as shown in Fig. 1. At the lower end of the minor portion 60 of the valvemember 58 is a shallow channel 69 which extends circumferentially around the valve member and Y constitutes a port for connecting the primary passages 30 with the discharge passage or port 33, as shown in Fig. 1, when the valve member 58 is in raised position, and'for connecting the secondary passages 32 with the discharge passage 33, as shown in Fig. 16, when the valve member 58 is inlowered position. Sldable within the bore of the valve liner 45 in huid-tight relation, and movable within the bore of the valve member 58 in spaced relation thereto, between the raised and lowered positions thereof shown in Figs. 1 and 16,'is a pilot rod 1|, the lower end of which is connected to the upper end of a power piston 12 adapted to be reciprocated within the power cylinder 4|. A cavity 13 formed in the lower endV of the plug body 43 constitutes a continuation of the bore of the cylinder liner 44, and the portion thereof above ports 14 forms a dashpot chamber for holding a body of uid to stop the upward movement of the power piston 12 with a cushioning eiect. The ports 14 communicate with vertical passages 15 formed in the wall of theA plug body 43 so as to connect with the lower ends of the primary fluid passages 30 of the valve body 23.

The secondary iluid passages 32, which lead downwardly from the ports 3|, connect with uid passages 16 having the form of grooves in the external face of the plug body 43. The lower end of the power cylinder 4| has threads 11 for connecting it to an intermediate plug 18 which has an upwardly projecting extension adapted to engage the lower end 8| of the liner 44 in huid-tight engagement. In the upper end of the extension 80 a dashpot cavity 82 is formed, the side wall 83 thereof having ports 84 which connect the lower cylinder space 85 with an annular space 86 formed between the extension 80 and the wall 81 of the power cylinder 4|, which space 86is connected to the chamber 42 at the upper end of the ycylinder 4| by means of coaxial passages 88 which are formed between the cylinder 4| and its liner 44.

A piston rod 90'extends downwardly from the power piston 12 through the intermediate plug 18 and a valve structure 9| disposed at the lower end thereof into engagement with the upper end of a pumping piston 92 which is reciprocable in a pumping cylinder 93. The pumping cylinder .93 has the same characteristics as the power cylinder 4| in' having anupwardly extending wall 94 forming a cavity 95 adjacent the lower end of the intermediate plug 18 to which it is connected by means ,of threads 98. The lower end of the cylinder 93 comprises a downwardly extending wall 91 which forms a cavity.98 adjacent the upper end of an extension |00 forming a part of a lower plug to which the wall 91 is connected by means of threads |02. By means of threads |03, a tting |04 is connected to the lower end of the lower plug |0|, this tting |84 hav-ing a downwardly tapering wall |05 at the lower end thereof adaptedto engage a conical seat |06 formed in a valve insert member |01 which is supported in a 4reducing tting |08 which is connected by means of threads ||0 to the lower end of a string of pipe which extends to the top of the well and is of such diameter that the pump structure may be lowered therein into engagement with the seat member |01 as shown in Fig. ,3. The lower end of the fitting |08 is threaded at ||2 to receive an intake member ||3 which forms a gas anchor. I

It will be noted that the pilot rod 1|, the power piston 12, the piston rod 90 and pumping piston 92 are all equipped with axial passages I4, which passages ||4 connect with an axial passage ||5 extending' through a rod ||6 which projects downwardly from the pumping piston 92 through the valve structure |1 contained within the cavity 98, and through the lower plug |0| into a tubular member ||8 whichl extends downwardly from the lower plug |0| and h'asthe lower end thereof closed by means of a wall I9. Oil from the well, which is tobe pumped by the pumping piston 92, passes into the lower endof the pump structure through an opening |20 in the foot fitting |04, upwardly through the space within the fitting |04,\.as indicated by arrows |2I, through coaxial openings |22 Aformed within the wall of the lower plug |0| into the annular space |23 formed in the cavity 98 around the valve structure ||1, and through coaxial passages |24 `between the pump cylinder Wall 93 and its liner |25, which coaxial passages |24 connect the space |23 with the space |26 in the cavity 95 around the valve structure 9|. Each valve structure 9| and ||1 includes an annular insert body |21 having. three L-shaped passages |28 through which oil may pass from v by means of spring-pressed rings |35. yAlso form'ed in the insert bodies |21 is a plurality of coaxial passages |36. These passages connect the passages |30 with annular spaces |31 formed respectively in the lower and upper ends of the plugs 18 and |0I, three being passages |38 in the plugs 18 and |0 connecting the spaces 31 with the exterior of the plugs and consequently with the annular space |40 formed around the pump structure |`9 within the piping Accordingly, in the operation of the pump, oil is drawn from the spaces |23 and |26 through the passages |28 into the ends of the pumping cylinder and is forced from the pumping cylinderv through the passages |36 and |38 into the space |40 within the piping which carries the-discharged oil to the top of the well.V The discharge passage 33, Figs. 1 and 5, also connects with thel space |40 so that the discharge from the power cylinder combines with the pumped oil in the piping and is conducted to the top of the well.

An important feature of the invention consists in the use of a valve member for controllingthe flow of uid under pressure to the upper and lower ends of the power cylinderA this valve member being moved by uid pressure from one position to another thereof and being positively held in such positions between the proper times for the movement thereof. The valve member 58 may be reasonably termed a piston valve for the reason that it is moved between the primary and secondary positions thereof shown in Figs. 16 and 1 respectively by pressure of uid against its ends.

The valve structure is very greatly simplified by use of what may be termed the differential principle. In this valve mechanism, as shown in Figs. 1 and 16, iluidunder pressure is ydelivered downwardly through the tube 2| and passes through a screen or filter member |4| into a pressure space |42 formed within the upper end of the valve body 23. Accordingly, the pressure of this uid is constantly exerted against the upper end face 'of the piston valve 58 and tends to move the piston valve downwardly from the secondary or raised position in which it is shown in Fig. 1 to the primary or lowered position in which it is shown in Fig. 16. The major portion 62, Fig. 14, of the piston valve 58 is of larger cross-sectional area than the minor portion 68, and means are provided for intermittently producing in. the space 41 below Vthe lower end of the piston valve 58 a fluid pressure sufficient to overcome the pressure of iluid in the pressure space |42, to move the piston valve 58 upwardly. Release of the pressure in the space 41 results in a downward movement of the piston valve 58 under pressure of fluid in the pressure space |42.

For purpose of explanation, let it be assumed that with the piston valve 58 in the raised position shown in Fig. l, iluid under pressure from the space |42 has been applied through the bore of the piston valve 58, ports 61 of the valve member 58, ports 3|'of the valve body 23, passages 32, 16, 88, and 84 into the lower cylinder space 85, and that the power piston 12 has been raised from a lowered position such as shown in Fig. 17 to the' raised position in which it is shown in Fig. 1. Accordingly, then, it may be assumed that the pilot rod 1| has just reached its raisedA position so as to bring passage means |43, comprising a plurality of vertical grooves formed therein, as shown in Figs. 1, 10 and 11, into a position to connect the port 52 leading into the space 41 with the port 55 which communicates with the space |48 exterior of the pump structure i8 through passages 56, 51, 31, and 38. In a pumping mechanism of the character shown, the pressure in the space |48 of the delivery column may be considered a low fluid pressure in view of the fact that it is substantially one-half the pressure of the iluid applied to the space |42. Accordingly, thebringing of the passage means |43 into conjunction with the ports 52 and 55 will result in a decrease of the pressure within the space 41 to a low value, and the high uid pressure in the space |42 will operate to move the valve member 58 downwardly, discharging low pressure uid outwardly through the port 52 and the passages |43,

etc., which are at this time connected thereto as the result of the pilot rod 1| reaching its raised position as hereinbefore described, the result being, therefore, that the valve member will move downwardly from the raised secondary position shown in Fig. 1, in which it connects the primary passage 38 with discharge through the passage 33 and connects the passage 32 with iiuid under pressure through the port 3|, to its lowered primary. position shown in Fig. 16, in which the primary valve ports 85 willl connect the-primary passages 38 with fluid under pressure through'the ports 28, and the shallow channel 69 will move down intosuch position as to connect the ports 3| at the upper ends of the passages 32 with the discharge port or passage 33, thereby permitting fluid under pressure to ilowinto the space or cavity 13 at the upper end of the power cylinder,

and fluid` from the lower cylinder space 86 to discharge through the passage 32 and the ports 3|, 69, and 33 into the space |48.

An especial feature of the invention is to provide a slow travel of the piston valve 58 as it approaches the points in its travel at which pressure iluid is admitted to the opposite ends of the power cylinder and at which oil is admitted to the pump cylinder. It will be noted that the port 52 leading into the space 41 is disposed a short distance above the bottom of. the space 41 and that, as best shown in Fig. i4', the'lower end of the piston valve 58 has an annular wall |44 internally formed so as to cover the port 52 when the piston valve 58 nears the lower end of its movement, as shown in Fig. 18, thereby shutting off escape of fluid through the port 52 and the passage means |43, etc., which are at'this time connected therewith.

The final downward'movement of the piston valve 5 8 is then controlled by a novel form of throttling means which controls the escape of fluid from the space 41 below the piston valve 58. The throttling means-includes upper and lower -helical grooves |45 and |46 formed in the outer surface of the valve liner 45, the upper groove I 45 extending in a helix downward from the upper end surface of the liner and the lower groove |46 extending in ahelix upward from an, annular the space |48 and the space 41 below the piston valve 58. At the time the wall portion |44 of the piston valve 58 rst closes the port 52, the ports 61 of the piston valve 58 will connect with the channel 36 which is in communication through the passage 35 with the discharge fluid in the space |48 exterior of the valve bod:7 23, and fluid from the lower end of th space 41 below the piston valve 58 may flow upwardly through the passage |49, the space |48 and slowly through the throttling means represented by the long spiral groove |46, thence through the ports 81, the channel36, and the passage 35 to the exterior, thereby permitting the piston valve to move to its extreme lowered position.

When the piston valve 58 reaches its lowered or primary position, as shown in- Fig. 16, the power piston 12 will be moved downwardly as the result of the application of fluid under pressure from the space |42 through the primary passage 38 and associated passage and port means, as hereinbefore described. When the power piston 12 reaches the lower end of.v its downward movement, passage means |58, preferably comprising a plurality of vertical grooves formed near thc upper end of the pilot rod 1| will be brought into the position in which they are shown in Fig. 16,

connecting the upper part |5| of the bore of the liner 45, which now contains fluid under high pressure, with the channel 48 in the bore of the liner 45, which channel connects through the ports 58 with'the space |48 below the helical groove |46. Accordingly, fluid under high pressure is the conducted throughthe space |48 and the passage |48 into the extreme lower end of the space 41 below the major portion 62 of. the'piston valve 58. V'I'he pressure of the fluid now exerted against the lower end face of the piston valve 58 will be the same as the pressure of iluid exerted against the upper end thereof, but in view of the fact that the area of the lower end of the pistony valve 58 is greater than the area of the upper end thereof, the piston valve 58 will be forced to/move upwardly from the position in which it is yshown in Fig. 16 toward the position in which it is shown in- Fig. 1.. As the piston valve 58 moves upwardly, the wall |44 at the lower end thereof, will cover the port 58, as shown in Fig. 18, sci-that the fluid under pressure can no longer entertherethrough but at this time the upper end of the space or channel |48 will have reached a position in which it communicates with the upper helical groove 45, and a restricted flow of fluid through the throttling means represented by the helical groove |45 and the space |48 and the passage |49 into the space 41 below the valve 58 will complete the upward movement of the piston valve 58 to its secondary position shown in Fig. 1.

In order to avoid excessively slowing up the operation of the valve during its slow-moving period described above, I prefer to arrange the throttling means of the valve so that the valve moves very slowly during the early part of the admission of oil to the pump cylinder so that hydraulic shock is avoided and then increases in speed .during the rest of its travel. One efflcient means for accomplishing this function, which I prefer to utilize, comprises helical grooves |45 and |46 which-are graduated in depth, the deeper portions 'of the respective grooves being at the point at which they communicate with the upper end surface of the liner andthe annular channel |41, respectively as shown in the drawings. In operation, when the annular wall'l44 rst covers the port 52 on the downward movement of the valve, the position in which it is shown in Fig. 17, the ports 61 are in`communication with the shallower portionof the groove |46, and a very gradual flow of uid through the passage |49, the space |48, and the groove |46, into the ports 61 occurs, resulting in a very slow movement of the piston valve during the initialA opening of the primarypassage 30 and during the early part of the admission of oil to the pump cylinder. As the piston valve 58. moves downwardly, the deeper portions of the spiral groove |46 come into communication with the ports 61', allowing freer ow of the fluid therethrough so that the speed of the valve duringthe rest of its travel increases, the final speed thereof just before it reaches the ends of its stroke being preferably almost as great as its speed at the time the port 52 is initially cut off. I have found that the only time that extremely slow motion of the valve is'required to overcome hydraulic shocks, as stated above, is during the rst admission of oil. In other words, the important requirement is that the valve should start its slow movement just prior to the admission of oil and that during the period from cut-off to admission the piston stands still, as clearly indicated in the space-time diagram of Fig. 19. Therefore, if the valve continued to move through the rest of its stroke at the rate which is required to prevent-shock during the rst admission of oil, the time required for this movement would be excessive and the speed of the pump would be restricted. The provision of the throttling grooves |45 and 46, which are graduated in depth, controls the valve to produce slow motion thereof. only where required to prevent shock, andtherefore, the maximum speed of the pump can be greatly increased. It will be clear that the slow movement of the valve during the early part of the admission of oil and the subsequent increase in speed during the rest of its travel may be controlled as desired by varying A the depth of the helicalgrooves |45 and'I4S. During theupward movement of the piston valve 58, the space |48 communicates rst with the shallower portions of the spiral groove |45, as access of the iluid under pressure to the space 4`| through the port 58 is cut off by the wall |44, and then as the valve 58 moves upwardly the space |48 communicates with deeper portions of the groove to allow increased flow of .oil there-- through into the passage |49 and the space 41 to accelerate the movement of the valve into its secondary position in which it reaches the upper end of. its stroke.

While the throttling means of the invention, above described, is suiclent under normal conditions to prevent shock, I prefer to utilize in conjunction therewith an additional means for modulating control of the delivery of fluid under pressure to the upper and lower ends of the power cylinder. As shown best in Figs. 14 and 15,. short channels |53, |54, |55, and |56 are formed reg spectively in the outer surface of the piston valve 58 so as to connect with ports 65, the upper end vof the shallow channel 69, the lower end of the shallow channel 69, and the ports 61, these short channels |53, |54, |55, and |56 varying from minimum to maximum in length, as shown in Fig. 15. The result of this construction is that when the piston valve 58 moves downwardly from the secondary position in which it is shown in Fig. l and approachesthe primary position in which it is shown in Fig. 16, its movement being slowed, as previously described, by the throttling means, just before the ports 65 reach the ports 28 the first communication of the valve ports 65 with the ports 28 will be through the short channels |53. This causes a slow introduction of fluid into the upper ends of the passages 30 which ,in addition to the slowmovement of the valve controlled by the throttling means eiectively reduces hammering or pulsatingV effect in the structure to a minimum. Likewise, as the lower edge of the shallow channel 69 of the piston valve 58 approaches the ports 3|, there will be a 'slow opening of the upper ends of the passages 32 to discharge pressure through the shortl channels |55. AThe short channels |54 and |55 operate in a similar flow modulating manner with respect to the ports 3| and 38 as the piston valve 58 moves into fully raised or secondary positionof Fig. 1.

An additional important feature of the mode l of. operation of the structure described comprising my invention is that the piston valve 58 is preevnted from premature movement from both its primary and secondary positions. This effect is accomplished by an auxiliary control of the fluid pressure against the ends ofthe piston valve v 58, and this purpose is served-by the throttling means of the invention represented by the helical grooves |45 and |46, together with the space |48 and the passages |49 associated therewith, as above described. In operation it will be noted that While the pilot rod 1| is traveling down wardly from its raised position and before it has reached the position in which it isr shown in Fig. 16, and when the piston valve 58 is in its lower or primary position, the helical groove |48 communicates through the ports 61, the channel 36, the passage 35, with the uid under low or discharge pressure in the space |48 surround ing the pump structure I8. During this time any leakage ofuid under pressure past the pilot rod 1| cannot exert an upwardly motivating force against the lower end of the piston valve 58 for the reason that such leakage fluid may pass out through the groove |46, the ports 6l, the channel 36, and the passage 35 to the space within the discharge column Likewise, during the time the piston valve is in raised position, as shown in Fig. 1, and the pilot rod 1| is traveling upwardly, the space 41 will be open to fluid under pressure through the helical groove |45, the space |48, and the passage |49, the groove |45 being oi such capacity that it will supply fluid under pressure to the space 41 faster than fluid can escape from the space through the p'ort 52 and around the pilot rod below the port 52.

Although I have herein shown and described my invention in simple and practical form, it is recognized that certain parts or elements thereof are representative of other parts, elements, or mechanisms which may be used in substantially the same manner to accomplish substantially the same results; therefore, the invention is not to be limited to the details of construction disclosed herein but is to be accorded the full scope of the appended claims.

I claim as my invention:

l. A valve mechanism for a fluid motor of the character described having a piston operable in'a cylinder and having a passage for supplying pressure iluid to an end of said cylinder, including: a valve member movable between primary and secondary positions to alternately open said passage at a point intermediate said primary and secondary positions; means for moving said valve between said primary and secondary positions; and means for slowing the movement of. saidv valve at a point at which said passage is initially opened and for accelerating the movement of said valve from said point to said 'primary and secondary positions.

2. A valve mechanism fora fluid motor of the character described having a piston operable in a cylinder and having primary and secondary' passages supplying pressure uid to opposite ends of said cylinder, including: a valve member movable between primary and secondary positions in axial 'alignment with said cylinder and arranged to initially open said primary passage before it reaches said primary position and to initially open said secondary passage before it reaches said secondary position; means for moving said valve between said primary and secondary positions; means for slowing the movement of said valve as said primary passage is initially opened and for accelerating said valve during its subsequent movement into said primary position; and means for slowing the movement of Said valve as said secondary passage is initially opened and for accelerating said valve during its subsequent movement into said secondary position.

, 3. A valve mechanism for a duid motor of the character described having a piston operable in a cylinder and having passages for supplying pressure iluidto opposite ends of saidcylinder, including: a valve member adapted to be moved by fluid under pressure to alternately open said passages; means operatively connected to said piston for controlling the application of fluid to move said valve member; and means for slowing the movement of said valve member during the initial opening of said passages thereby and for accelerating the movement of said valve member during the completion of the opening of, said passages.

4. A valve mechanism for a fluid motor of the character described having a piston operable in a cylinder and having passages for supplying pressure fluid to opposite` ends of said cylinder, including: a valve member adapted to be moved by fluid under pressure to alternately open said passages; means operatively connected to said piston for controlling the application of fluid to move'said valve member; and throttling means -including walls forming restricted passages controlling the fluid moving said valve member to slow the movement of said valve member during the initial opening of said passages and to accelerate said valve member during the completion of its movement to fully open said passages.

5. A valve mechanism for a iluid motor of the character described having a piston operable in a cylinder, including: a valve casing having walls forming a valve bore disposed in axial alignment with said piston cylinder, said casing having passages for supplying pressure fluid to opposite ends of said piston cylinder; a valve member adapted to be moved in said bore by fluid under pressure to alternately open said passages; means operatively connected to said piston for controlling the application of fluid to move said valve member; and throttling means including walls forming restricted channels in said casing through which said fluid controlling said valve must flow during part of the movement of said valve,Y said channels being arranged to slow the movement of said valve during the initial opening of said passages and to allow acceleration of said valve during the completion of its movement to fully open said passages.

6. A valve mechanism for a fluid motor of the character described having a piston operable in a cylinder, including: a valve casing having walls forming a valve bore; a pilot rod connected to said piston extending into said bore; a tubular wall in said casing surrounding said pilot rod; a

tubular valve member in said bore and having a portion thereof disposed in an annular space defined by said tubular wall and the wall of said bore; walls forming pressure fluid passages in said casing for supplying pressure fluid to op-' posite ends of said cylinder; means including walls forming a fluid passage in said pilot rod for conducing uid to and from said annular space for controlling movement of said valve member to alternately open said pressure fluid passages; means carried by said valve for stopping flow `through said iluid passages in said pilot rod during part of the movement of said valve; and throttling means-including a restricted channel dened by the outer surface of said tubular wall and said valve member through which said iluid lcontrolling said valve must flow when the flow of said fluid in said fluid passages in said pilot rod is stopped, said channel being operable to slow said valve during the initial opening of said tubular wall and the wall of said bore; walls forming primary and secondary passages in sai-d casing for supplying pressure fluid to opposite ends of said cylinder; means including nuid passage means in said pilot rod for conducting uid into said annular space for controlling movement of said valve member to alternately open said primary and secondary passages; means carried by said valve for stopping ow of fluid through said fluid passages in said pilot rod just before 'said primary and secondary passages are opened;

and throttling means including walls forming grooves in the outer surface of said tubular wall cooperating with said valve member to define a ilrst restricted channel through which said iluid controlling said valve must iiow during opening of said primary passage and dening a second restricted channel through which said fluid must ow during opening of said secondary passage and said channels being graduated in area so that said valve is slowed during the initial opening of said passages and accelerated during the completion ofU-its movement to fully `open said passages.

8. A valve mechanism as specified in claim 7 yin which said grooves cooperating with said valve member to form said restricted channels are spiralled,

9. A valve mechanism of the character described, including: walls forming a valve bore; walls forming a pressure iiuid passage therein; a valve Imember adapted to be moved by uid pressure in said .bore to open said passage to supply pressure i'luid thereto; walls forming port means supplying uld for controlling said valve member; means carried by said valve member for closing said port means just before said passage is opened; and throttling means including a spiral groove formed in a wall of said bore through -which said fluid controlling said valve must flow when said port means is closed, the cross-sectional area of said groove being graduated and said groove being disposed so that said valve is slowedv during the initial opening of said passage and accelerated-`fduringi-the completion of its movement to fully open said pasage.

CLARENCE J. COBERLY. 

